This article offers concrete ways to modernize and advance existing laws governing the economics of couple relationships through fuller development and implementation of a “partnership of equals” theory. This is much needed because contemporary law does not adequately protect against financial vulnerabilities produced by partnering, and does not fairly share its benefits. As a result, law contributes to inequalities across a range of groups: between men and women; between cohabitants and married couples; and between same sex and opposite sex couples. Accordingly, I recommend a shift in law’s foundation and application. Couple’s law should be based on economic sharing behavior, broadly and specifically defined to include decision making as well as labor contributions, and should apply to unmarried as well as married couples. Further, law must recognize that sharing activities often importantly shape each partner’s financial situation, including, to an extent, earning power. Drawing on this foundation, I describe specific ways to actualize these principles in legal practice, focusing on when couples break up. Economic advantages and disadvantages that were developed jointly should be shared. At the same time, however, some financial resources are not or are not completely shaped by partnering. In addition, sharing patterns can vary, with the vast majority of married couples being strongly economically intertwined and cohabitants being widely variable. So, for all intimate partnerships, I propose that the legal standard should be an assessment of the degree of economic interdependence in the relationship with resulting rules for sharing property and income streams that vary accordingly. As ripe arenas for extending the reach of the partnership model I offer, for married couples, I focus on alimony and the recent push for guidelines and caps, and for cohabitants, I briefly consider support obligations and the nascent shift in U.S. law toward a joint property regime.